This invention generally relates to the inhibition of scale formation and deposition in aqueous systems by adding thereto an effective threshold amount of a copolymer of an acrylic acid and an alkoxyalkyl acrylate. In a preferred embodiment, the addition of a defined copolymer to an aqueous system results in unexpectedly high levels of scale inhibition. Specific applications contemplated herein are aqueous systems used in recirculating cooling towers, desalination, oil field applications particularly in seCondary oil recovery operations, flash distillation, as well as in aqueous systems such as milk, fruit juices, and sugar solutions. These copolymers are effective scale inhibitors against such scales as calcium phosphate, calcium carbonate, calcium sulfate, and are effective as dispersants of particulates and stabilizers of metal ions.
The invention disclosed herein is an improvement over the invention disclosed in U.S. Pat. No. 4,499,002 of inventors Masler and Amjad. Whereas the invention in U.S. Pat. No. 4,499,002 is directed to the use of a copolymer of an acrylic acid, an acrylamide, and an alkoxyalkyl acrylate, the invention herein is directed to the use of a copolymer as a scale inhibitor which is devoid of an acrylamide, i.e., a copolymer of an acrylic acid and an alkoxyalkyl acrylate This is very surprising since in col. 2, lines 31-33 of U.S. Pat. No. 4,499,002, it is stated that a copolymer of an acrylic acid and an alkoxyalkyl acrylate has very little activity as a scale inhibitor. The copolymers of acrylic acid and alkoxyalkyl acrylates noted in U.S. Pat. No. 4,499,002 were prepared in water whereas the same copolymers herein were prepared in a solvent. This appears to render the copolymers effective as scale inhibitors. It should be understood, however, that it is now possible to prepare the copolymers in water and have them effective as scale inhibitors.